The invention is generally directed to a portable studio hoist for use in raising and lowering lighting and other items from the pipe grids used in television studios, which are generally suspended from the building structure. The portable studio hoist is utilized to move studio lighting fixtures, which are affixed to the pipe grid vertically between the floor and the pipe grid. It may also be used to move lighting fixtures and other loads in other settings secured to appropriate fixed structural locations
Generally, existing hoists in theater and studio applications are intended for permanent installation, and typically, because of their size, weight and power requirements, must be installed as part of the building construction project. The hoists are affixed to the building's structural steel and permanently wired with three-phase power and a hard wired control circuitry, usually utilizing conduit wiring to meet building codes and electrical codes for permanent installations. As a result, the location of moving pipes must, therefore, be anticipated in the design process when a theater or studio is being built.
However, most U.S. television studios are equipped with pipe grids. These are static pipe structures suspended from the building structure. In turn, studio lighting fixtures are affixed to this grid. The fixtures are frequently moved and adjusted, requiring operators to climb ladders for access. Generally, standard hoists can only be added to the building steel or with the addition of structural steel because the pipe grid does not have sufficient weight bearing capacity to support the weight of these hoists, and lifted weight, which generally run about 750 or more pounds.
The pipe grids are typically equipped with lighting power distribution strips carrying power to all locations on the grid. This permits optimum flexibility for the lighting. The power, however, is single-phase 120 VAC, which is sufficient for the lighting. If a typical hoist is added to this system, three-phase power must be run to that location, which becomes a fixed location for that hoist. Accordingly, there is a need for an improved hoist that can carry a modest payload, up to about 300 pounds, and could be quickly moved anywhere on a grid and be quickly provided with existing power. That need is typically only identified by the studio operators after the studio has been built and in use for a time and, thus, there is also a need for the portable hoist to be of a sort which can be brought to a site when and as needed or be rented from a lighting rental house, together with studio lighting fixtures. It is also necessary to develop a portable hoist system which can be moved around the grid to areas where workers are either adding, removing or modifying studio lighting fixtures in connection with a production.